About 7-10 percent of all people suffer daily, and about 25-40 percent monthly, from pain, discomfort and/or symptoms associated with episodic heartburn. Episodic heartburn is defined as the sensation of burning under the sternum (breastbone) and is usually associated with the ingestion of different foods. Episodic heartburn has also been referred to as "sour stomach," "indigestion," and "waterbrash/regurgitation." Although different foods, such as coffee, mints, fatty foods, alcohol, and chocolate, are usually implicated in the etiology of episodic heartburn, these symptoms can be caused by any type of food in certain people. Moreover, in many people, there is no inciting agent that can be identified, rather the disorder occurs without any known provocation.
At present, the primary treatment is based upon the neutralization of gastric acid and pepsin with antacids, such as, for example, aluminum hydroxides, calcium carbonates, magnesium hydroxides and sodium bicarbonates. Of less importance, treatment is based upon the inhibition of secretion by histamine H.sub.2 -receptor antagonists, such as cimetidine and ranitidine.
Unfortunately, both of these treatments have proven to be inadequate. The problem with antacids is that they provide only transient relief. This disadvantage is emphasized in many people at night where symptomatic relief is not provided. The problem with histamine H.sub.2 -receptor antagonists is that relief is typically not experienced until about forty minutes to about two hours after the medication is ingested. Moreover, the simultaneous administration of antacids and histamine H.sub.2 -receptor antagonists have been discouraged based upon studies demonstrating that antacids decrease absorption and subsequent blood levels of histamine H.sub.2 -receptor antagonists, such as cimetidine and ranitidine. See, for example, Steinberg, W. et al.: N. Engl. J. Med., 307:400-404 (1982), and Frislid, K. et al.: Br. Med. J., 286:1358 (1983); and Mihaly, G. W. et al.: Br. Med J., 285(6347):998-9 (Oct. 9, 1982).
Consequently, there is a need for a treatment which can effectively provide both instant and sustained relief from pain, discomfort and/or symptoms associated with episodic heartburn in humans.